Friday, November 27, 2009

Telecube modules are cube shaped modules with faces that can extend out doubling the length of any dimension. Each face "telescopes" out, thus the name. Each face also has a latching mechanism to attach or detach from any other face of a neighboring module. We have experimented with shape memory alloy and permanent switching magnet technologies in various versions of this system.

UWE investigates evolving 'swarm' robots
The University of the West of England (UWE) is a partner in 'Symbrion', a ground breaking new European funded project, which will investigate the principles of how large groups (swarms) of robots can evolve and adapt together into different organisms based on bio-inspired approaches.

The aim of the project is to develop the novel principles behind the ways in which robots can evolve and work together in large 'swarms' so that – eventually - these can be applied to real-world applications. The swarms of robots are capable of forming themselves into a 'symbiotic artificial organism' and collectively interacting with the physical world using sensors.http://info.uwe.ac.uk/news/uwenews/article.asp?item=1231

Self-assembling Robot Video

Robots with a mind of their own Video

Scientists are now building a new kind of robot capable of self-assembly and doing tasks too difficult or too dangerous for human beings.

Self-Replicating Repairing Robots Video
Engineers at Cornell University have designed this odd-looking machine that can rebuild itself and also could perform repairs on itself.

Wednesday, November 18, 2009

MTRAN modular robots have been intensively investigated mainly by universities and research institutes in Japan and USA since around 1990 as the robots' versatility, flexibility and fault-tolerance has been attracting researchers' interest. Experiment of self-reconfiguration by 9 moduleAs MTRAN is rather smaller and lighter than ever, both self-reconfiguration and dynamical motion of a group is made possible

http://staff.aist.go.jp/e.yoshida/test/research-e.htm

PolyBot

PolyBot is made up of many repeated modules. Each module is virtually a robot in and of itself having a computer, a motor, sensors and the ability to chains PolyBotattach to other modules. In some cases, power is supplied off board and passed from module to module. These modules attach together to form , which can be used like an arm or a leg or a finger depending on the task at hand.

http://www2.parc.com/spl/projects/modrobots/chain/polybot/index.html

PolyBot

Polypod is a bi-unit modular robot. This means that the robot is built up of exactly two types of modules that are repeated many times. This repetition makes manufacturing easier and cheaper. Dynamic reconfigurability allows the robot to be highly versatile, reconfiguring itself to whatever shape best suits the current task. To study this versatility, locomotion was chosen as the class of tasks for examination.http://www2.parc.com/spl/projects/modrobots/chain/polypod/index.html

Digital Clay

At Xerox PARC it is a subset of the modular robotics project. As such it is a stripped down version of a modular robot. That is, there is a) no active coupling and b) no actuation for producing module to module motions. Changes to an assembly of modules is made by a user. But it embodies one very important aspect—that the modules have some capacity to sense or know their own orientation in space with respect to other modules. As such it may be a useful hardware system for testing software, communications, power distribution for physically modular and reconfigurable systems.http://www2.parc.com/spl/projects/modrobots/lattice/digitalclay/index.html

Modular Snake Robots

Snake robots can use their many internal degrees of freedom to thread through tightly packed volumes accessing locations that people and machinery otherwise cannot use. Moreover, these highly articulated devices can coordinate their internal degrees of freedom to perform a variety of locomotion capabilities that go beyond the capabilities of conventional wheeled and the recently developed legged robots. The true power of these devices is that they are versatile, achieving behaviors not limited to crawling, climbing, and swimming.

http://www.cs.cmu.edu/~biorobotics/projects/modsnake/modsnake.html

MTRAN3 Modular Robot

Modular robot reassembles when kicked apart

A robot developed by roboticists at the University of Pennsylvania is made of modules that can recognise each other.

Sunday, November 08, 2009

The HoverBot CAn Electrically Powered Flying RobotSUMMARYThis paper describes the development of a fully autonomous or semi-autonomoushovering platform, capable of vertical lift-off and landing without a launcher, and capable ofstationary hovering at one location. The idea to build such a model-sized aerial robot is not new; several other research institutes have been working on aerial robots based on commercially available, gasoline powered radio-control model helicopters. However, the aerial robot proposed here, called the HoverBot, has two distinguishing features: The HoverBot uses four rotor heads and four electric motors, making it whisper-quiet, easy-to-deploy, and even suitable for indoor applications. Special applications for the proposed HoverBot are inspection and surveillance tasks in nuclear power plants and waste storage facilities.

Without a skilled human pilot at the controls, the foremost problems in realizing a model helicopter-sized flying robot are stability and control. It is necessary to investigate the stability and control problems, define solutions to overcome these problems, and builde a prototype vehicle to demonstrate the feasibility of the solutions. The proposed HoverBot will have eight input sensors for stability and control, and eight output actuators (4 motors and 4 servos for rotor pitch control). The resulting control system is a very complex, highly non-linear Multiple-Input Multiple-Output (MIMO) system, in which practically all input signals affect all output signals. A surprisingly simple experimental control method, called additive control, is proposed to control the system. This method was successfully used in the current experimental prototype of the HoverBot (although with fewer input signals). It is also proposed to investigate two alternative control methods, adaptive control and neural networks, both of which appear to be especially suitable for the Multiple-Input Multiple-Output control problem.If successful, the project will result not only in a working prototype of a flying robot, butit will also provide important insight into the functioning of various control methods for verycomplex MIMO systems.

Control of the HoverBotThe control system of the HoverBot is designed to allow either fully autonomous operation or remote operation by an unskilled operator. To either, the HoverBot will appear as anomnidirectional vehicle with 4 degrees of freedom: (1) up/down (2) sideways, (3) forward/backward, and (4) horizontal rotation.

Creation of a Learning, Flying Robot by Means of EvolutionAbstractWe demonstrate the first instance of a realon-line robot learning to develop feasibleflying (flapping) behavior, using evolution.Here we present the experiments and resultsof the first use of evolutionary methods fora flying robot. With nature's own method,evolution, we address the highly non-linearfluid dynamics of flying. The flying robot isconstrained in a test bench where timing andmovement of wing flapping is evolved to givemaximal lifting force. The robot is assembledwith standard o®-the-shelf R/C servomotorsas actuators. The implementation is a conventional steady-state linear evolutionary algorithm.

ROBOTFive servomotors are used for the robot. They arearranged in such a way that each of the two wings hasthree degrees of freedom. One servo controls the twowings forward/backward motion. Two servos controlup/down motion and two small servos control the twistof the wings. The robot can slide vertically on two steelrods. The wings are made of balsa wood and solar,which is a thin, light air proof ¯lm used for modelaircrafts, to keep them lightweight. They are as largeas the servos can handle, 900 mm.

http://fy.chalmers.se/~wolff/AWNGecco2002.pdf

Energy-efficient Autonomous Four-rotor Flying RobotControlled at 1 kHzAbstract—We describe an efficient, reliable, and robust fourrotorflying platform for indoor and outdoor navigation. Currently,similar platforms are controlled at low frequencies dueto hardware and software limitations. This causes uncertaintyin position control and instable behavior during fast maneuvers.Our flying platform offers a 1 kHz control frequency andmotor update rate, in combination with powerful brushlessDC motors in a light-weight package. Following a minimalisticdesign approach this system is based on a small number of lowcostcomponents. Its robust performance is achieved by usingsimple but reliable highly optimized algorithms. The robot issmall, light, and can carry payloads of up to 350g.

THE FOUR-ROTOR HARDWAREA. General designOur flying robot has a classical four rotor design withtwo counter rotating pairs of propellers arranged in a squareand connected to the cross of the diagonals. The controllerboard, including the sensors, is mounted in the middle of thecross together with the battery. The brushless controllers aremounted on top of the booms. Figure I shows a photographof the flying robot. The weight without battery is 219g. Theflight time depends on the payload and the battery. Witha 3 cell 1800mAh LiPo battery and no payload the flighttime is 30 minutes. We measured the thrust with a fullycharged 3 cell LiPo (12.6V) at 330g per motor. With fourmotors the maximum available thrust is 1320g. Since thecontrollers need a certain margin to stabilize the robot alsoin extreme situations, not all the available thrust can be usedfor carrying payload. In addition, efficiency drops and asa consequence flight time decreases rapidly with a payloadmuch larger than 350g. Because of this we rate our robot fora maximum payload of 350g.

With a 350g payload, a flight time of up to twelve minutescan be achieved. The maximum diameter of the robot withoutthe propellers is 36.5cm. The propellers have a diameter of19.8cm each. The sensors used to stabilize the robot are verysmall and robust piezo gyros ENC-03R from Murata [14].The second design iteration of this robot is already functionalbut not fully tested and characterized experimentally. Thissecond version additionally has a three axial accelerometerand relies on datafusion algorithms, still running at 1kHz,to obtain absolute angles in pitch and roll.

The ROBUR project: towards an autonomousflapping-wing animatAbstractFlapping-wing flight is not applicable to huge aircrafts, but has a great potential for micro UAVs - as demonstrated by real birds, bats or flying insects. The ROBUR project aims at designing a robotic platform that will serve to better understand the design constraints that this flying mode entails, and to assess its capacity to foster autonomy and adaptation. The article describes the major components of the project, the tools that it will call upon, and its current state of achievement.Research on flapping flight maneuverabilityA generic model of a flapping wing aircraft has been designed, in which lifting surfaces aremodelled by a set of articulated panels (figure 2). In a first stage, this model will be used todesign a simple periodic controller for such a platform by using evolutionary algorithms (figure3). This controller is expected to generate a periodic, horizontal, flapping flight at a constantspeed.

Physical model used in this project.

http://animatlab.lip6.fr/papers/Doncieux_JMD2004.pdf

Quad-Rotor Flying Robot

New German UAV – microdroneA high technology very small UAV made in germany by microdrone GmbH. Can reach an altitude of 400m and stay in the sky for 30 minutes

Saturday, August 22, 2009

Anna KondaThe fire fighting snake robotAnna Konda was developed in order to demonstrate the SnakeFighter concept. The robot is to our knowledge the biggest and strongest snake robot in the world and also the first water hydraulic snake robot ever constructed.

Embedded control systemMicrocontrollers (AVR ATmega128) are used to control the motion of the joints of Anna Konda. A communication bus through the robot allows for communication between the microcontrollers and a dedicated controller in the head of the robot (the brain). The brain can communicate with an external computer through a wireless connection based on Bluetooth. This allows the robot to be remotely controlled by an operator.http://www.sintef.no/Home/Information-and-Communication-Technology-ICT/Applied-Cybernetics/Projects/Our-snake-robots/Anna-Konda--The-fire-fighting-snake-robot/

Robot spycan survive battlefield damageBentley and his colleague Siavash Haroun Mahdavi borrowed a trick from evolution to allow their robot to adapt to damage. The snakebot is made up of modular vertebral units that "snap" together to form a snake-like body (see graphic). Each unit contains three separate "muscles" running down its length. The muscles are made out of wires of a shape-memory alloy called nitinol, an alloy of nickel and titanium whose crystal structure shrinks when an electric current is applied to it. Usefully, it regains its original shape and length once the current is removed. To make the snakebot move in a particular direction, a current is applied to certain wires. When the current is removed, the wires spring back and the robot will jump forward.

http://www.newscientist.com/article/dn4075

SnakebotSnakebots that are being developed will be able to independently dig in loose extraterrestrial soil, are smart enough to slither into cracks in a planet's surface, and are capable of planning routes over or around obstacles

Sea snakes live in water, and even terrestrial snakes sometimes show swimming on water surface. In fact, the mechanism of snakes’ propulsion is almost same both in water and on ground. An amphibious snake-like robot ACM-R5 (Fig. 1) takes advantage of this fact. It can operate both on ground and in water undulating its long body (Fig. 2, Fig. 3).

The joint of ACM-R5 consists of an universal joint and bellows (Fig 4). It was developed on the basis of the previous model HELIX, which was designed for research of spirochete-like helical swimming. An universal joint plays a role of bones, and bellows do a role of an integument. ACM-R5 can form a smooth shape due to this joint structure, and it is important for effective locomotion. To be precise, the universal joint has one passive twist joint at the intersection point of two bending axis to prevent mechanical interference with bellows.

http://www-robot.mes.titech.ac.jp/robot/snake/acm-r5/acm-r5_e.html

Robot Snake Vedio

Cool Robot SnakeI want one of these! THINK IT'S FAKE? Check out Dr. Gavin Miller's site... http://www.snakerobots.com/... This is the S5 version of S1 thru S7. We HAVE the technology! Some of you younger puppies

Monday, July 27, 2009

INTERFACING AN ANALOG COMPASS TO AN EMBEDDEDCONTROLLERAbstractThis paper describes the development of a compass sensing unit for use on a remotely operated vessel. The sensor determines the direction of the vessel’s path to aide the user in operating the boat wirelessly through a laptop. The system provides information tofacilitate tracking and controlling the boat when it is not easily seen by the operator. The selected compass, Dinsmore R1655 analog compass sensor, was used in conjunction ofan 8051 microcontroller to provide the necessary data. The system was able to read an analog value from the sensor and convert it to digital direction. The paper will describe the system design and present test results.

http://www.icee.usm.edu/icee/conferences/asee2007/

papers/630_INTERFACING_AN_ANALOG_COMPASS_TO_AN_EMBE.pdf

Microcontroller Design Final Project: Digital CompassThe goal of this project is to build a digital compass that displays both the direction and cardinal points on a television. Other functionalities were added to complement the sensor interface, such as, temperature display, magnetic declination input and disability option.

Electronic Compass Design using KMZ51 and KMZ52This paper describes how to realize electronic compass systems using the magnetoresistive sensors KMZ51 and KMZ52 from Philips Semiconductors. Therefore, firstly an introduction to the characteristics of the earth´s magnetic field is given. In the following, the main building blocks of an electronic compass are shown, which are two sensor elements for measuring the x- and y-components of the earth field in the horizontal plane, a signalconditioning unit and a direction determination unit.

Electronic compass is often used to provide the absoluteheading reference for tracking the user’s head and handsin Virtual Reality (VR) and Augmented Reality (AR),especially for outdoor AR applications. However,compass is vulnerable to environment magnetismdisturbance. Existing compass calibration methodsrequire complex steps and true heading reference whichis often impossible to be obtained in outdoor ARapplications, and is useful only when compass is inhorizontal plane. An autocalibration method without theneed of heading reference and redundant sensors isproposed in this paper. First the compass error modelbased on physical principle is presented, then thealgorithm to calculate the compensation coefficients witha set of sample measurements of the sensors in thecompass is described. Because the influence of theenvironmental disturbance has been effectivelycompensated, the calibrated compass can providedaccurate heading even when it is under large tilt attitude.

The HMC1052 two-axis magnetic sensor contains two Anisotropic Magneto-Resistive (AMR) sensor elements in a singleMSOP-10 package. Each element is a full wheatstone bridge sensor that varies the resistance of the bridge magnetoresistorsin proportion to the vector magnetic field component on its sensitive axis. The two bridges on the HMC1052 areorientated orthogonal to each other so that a two-dimensional representation of an magnetic field can be measured. Thebridges have a common positive bridge power supply connection (Vb); and with all the bridge ground connections tiedtogether, form the complete two-axis magnetic sensor. Each bridge has about an 1100-ohm load resistance, so eachbridge will draw several milli-amperes of current from typical digital power supplies. The bridge output pins will present adifferential output voltage in proportion to the exposed magnetic field strength and the amount of voltage supply acrossthe bridge. Because the total earth’s magnetic field strengthis very small (~0.6 gauss), each bridge’s vector component ofthe earth’s field will even be smaller and yield only a couple milli-volts with nominal bridge supply values. Aninstrumentation amplifier circuit; to interface with the differential bridge outputs, and to amplify the sensor signal byhundreds of times, will then follow each bridge voltage output.

Sunday, July 05, 2009

AROBOT ARM TUTORIALThe robot arm is probably the most mathematically complex robot you could ever build. As such, this tutorial can't tell you everything you need to know. Instead, I will cut to the chase and talk about the bare minimum you need to know to build an effective robot arm.

High efforts are put in the mechanical design of industrial manipulators to obtain high position accuracy using rigid joint actuators and rigid arms resulting in heavy masses of arms. For safety reasons, they can only be used in environments strictly separated from humans. Thus they stand in remarkable contrast to animals and humans with their much better relationship from payload to arm weight, and its concurrent high movement quality by "intelligent" control.

I present the results, hoping it will be useful to other people who are also interested. This robotic arm is a little demonstration, it uses stock servo-motors normally used in RC models, and is controlled from a pc, attached with a serial cable.

this is the most advance version of “Pick n Place Robot” perhaps and most popular and widely used in recent industries. A person from a remote place can comfortably control the motion of robotic arm without any wire connection.

RoboSim is a very simple simulation system for a 6 degres of freedom robot manipulator. The basic functions of the control panel are to move the manipulator either in joint coordinates or in cartesian coordinates. It is also possible, to change the view position or change length and color of the links. Joint weights may be set, in order to favor movement of individual joints versus others

torsoHead LeftArm stepper motors showing, stepper motor control board, and cardboard hand or fingers. The cardboard fingers are place holders and have been cut to the same proportions as a human hand. This is needed to gauge the real distance for the arm's reach. The fingers will be replaced with the finished hand.

Sunday, May 31, 2009

Fish Robot ProjectPrinciples of the Swimming Fish RobotWe can say that fish swim with pushing water away behind them, though fish swim by various methods. As the well-known categories for the swimming fish, a zoologist, C.M. Breder classified into the following three general categories based on length of a tail fin and strength of its oscillation (see the figure to the right).(a) Anguilliform: Propulsion by a muscle wave in the body of the animal which progresses from head to tail like the Eel.(b) Carangiform: Oscillating a tail fin and a tail peduncle like the Salmon, Trout, Tuna and Swordfish.(c) Ostraciiform: Oscillating only a tail fin without moving the body like the Boxfish.

Fish Robot (Analysis And Mathematical Modeling of Thunniform Motion)This research, Institute of Field Robot (FIBO) use the yellow-fin prototype tuna to build the robot because of its movement ability in high speed for a long time, thunniform mode, which make us believe that its movement will be the most efficient locomotion mode than other aquatic mammals. Additional, the body profile is both symmetrical in horizontal and vertical plane, which is helpful for finding out the equation of motion.

Model Fish Robot, PPF-06iIt was confirmed that the PPF-06i swims with swimming speed of about 0.1 m/s using the micro-computer. Also, it was confirmed that the PPF-06i turns with turning diameter of about 1 m, when the tail swings to one side during the turning. I think that one of the above purposes, (i) Swimming of the fish robot using R/C servomotors controled by a micro-computer, was achieved approximately.On the other side, another of the purposes, (ii) Simple control by sensors, has not been achieved.

Design Concept of the PPF-08iThe model fish robot named PPF-08i has been developed after considering the previous model fish robots, PPF-06i and PPF-07i. The design concept and purposes are as follows:(1) Simple structure(2) Small size(3) High turning performance (small turning diameter),(4) Controlled by a microcomputer,(5) A basic model of the group robots.

The figure to the right shows the structure of the PF-600. A battery, R/C receiver and two servos are located in the body. Two rods connect link mechanisms in the two tail peduncles (forward and tail peduncles), and finally the tail fin through rod seals. For sliding rod seals, slide bearings are used. Other parts that do need to move are sealed with "O" rings.http://www.nmri.go.jp/eng/khirata/fish/experiment/pf600/pf600e.htm

Fish Robot ResearchOn the Design of an Autonomous Robot FishAbstract—A fish-like propulsion system seems to be aninteresting and efficient alternative to propellers in smallunderwater vehicles. This paper presents the early designstages of a small autonomous robotic vehicle driven by anoscillating foil. It describes the preliminary dimensioning ofthe vehicle and the selection and sizing of the necessaryactuators according to the project’s objectives and constraints.Finally there is a description of the control systemimplementation for the tail’s motion.

Fish swimming is classified as carangiform, anguiliform,thunninform and ostraciform, depending on the percentageof their body that contributes in thrust production throughundulatory motions. According to this observation, thereare three alternative ways to design a robot fish, see Fig.

A simplified propulsive model of bio-mimetic robot fishand its realizationSUMMARYThis paper presents a simplified kinematics propulsive modelfor carangiform propulsion. The carangiform motion ismodeled as a serial N-joint oscillating mechanism that iscomposed of two basic components: the streamlined fishbody represented by a planar spline curve and its lunatecaudal tail by an oscillating foil. The speed of fish’s straightswimming is adjusted by modulating the joint’s oscillatoryfrequency, and its orientation is tuned by different joint’sdeflections. The experimental results showed that the proposedsimplified propulsive model could be a viable candidatefor application in aquatic swimming vehicles.

Body Construction of Fish Robot in Orderto Gain Optimal Thrust SpeedAbstractIn fish robot, hydrodynamic shape of its body determinesthe ability of the robot to swim. However, sometimes theswimming gait depends not only on the body, but also onthe frequency of tail undulation and body angle when itattempts to achieve fast swimming. Thrust speed becomesthe main objective in this research. Some variables whichare suspected as important variables influencing the thrustspeed were observed such as body shape, fin, frequencyof tail, and acceleration of tail. Results of investigationshow that there are some significant dependency amongthrust speed, frequency of tail undulation and body shape.In some conditions it was found that there was someoptimal condition for all parameters which pace the fishrobot towards fastest thrust speed.

Sunday, April 19, 2009

I use the Sharp GP2D12 non-contact infrared distance sensorfor determining the level of salt on the Water Softener Monitorproject. To test the Sharp sensor and to determine thevoltages at particular distances, I created a test apparatusout of a level and some machined plastic parts. This testsetup is compatible with the whole family of Sharp distancesensors, which are capable of different measurement distancesand different types of outputs

Design and development of a new sensorsystem for assistive powered wheelchairs

Abstract. Many disabled people experience considerabledifficulties when driving a powered wheelchair. Disabled peoplewho are not able to drive a powered wheelchair are seriouslylimited in their mobility. Several robotic assistive wheelchairshave been devised in the past. These wheelchairs are equippedwith range sensors, which detect obstacles and measure thedistance to the closest object. The authors are involved in thiskind of projects but, although many sensors exist commercially,they never found satisfactory range sensors for wheelchairapplications. After identifying these sensor requirements, thispaper presents the design of an optical ranging system, more inparticular a lidar (Light Detection and Ranging) scanner forwheelchair applications. Test results are reported to show thatthis scanner meets the identified requirements.

Sensor designAn approach that is now feasible at a modest pricetag, is using a lidar scanner (Light Detection AndRanging). Various systems already exist on the marketthat use light instead of the microwaves of the wellknown radar. A lot of research has been done on rangefinders, anti-collision systems for the car industry andpollution surveillance systems. Most of these systemsuse large aperture optical telescopes, powerful lasersand ultra fast electronic devices for the processing ofthe data to determinate the time of flight of the emittedand reflected light. They have a range of several hundredmetres up to a few kilometres. This performanceis much too high and most of these systems are ratherbulky and very expensive and are not always eye-safe.All these factors exclude their use on a wheelchair.The range of the obstacle detection system is from zeroup to 4 m. The determination of the time-of-flight inthis range, calls for ultra fast electronics (660 ps timeresolution for a spatial resolution of 10 cm) and putsa high demand on the switching characteristics of theopto-electronic components.In order to keep the complexity of the system, the demandon the opto-electronic components and the pricetag low, it is proposed to substitute the direct timeof-flight measurement by the measurement of a phaseshift. The light from an infra-red laser diode is amplitudemodulated with a signal of 5–20 MHz, dependingon intended range or resolution. The difference inphase between the signals from the transmitted and re-flected light is directly proportional to the distance. Theadvantages of this method are the much lower switchfrequency, the lower data processing speed and the useof less exotic components. The disadvantages are thelonger time it takes to get the measurement (some microseconds),compared to the time-of-flight measurement(some nanoseconds). This is only important in3D scanning systems where data throughput must bevery high. If the signal-to-noise ratio does not enablea stable measurement, the bandwidth of the processingcircuit must be further reduced, increasing processingtime. This is not necessarily a drawback in wheelchairapplications because the sample rate can still be suffi-cient high. Scanning in a horizontal plane can be performedby a rotating mirror, reflecting transmitted andreceived beams, or by rotating optics. The scanningrate of the lidar amounts to 5 rev/s.Different modules for the lidar scanner have beendeveloped:

Saturday, April 18, 2009

This project is a short range, infrared and ultrasonicscanner that uses a standard hobby servo to move thesensors and a color LCD screen to display the informationfrom the distance sensors. The information displayedon the LCD is an overhead view of the scanning area,with increments of distance from the distance sensors.

Hardware Details:The core of the project is the ATMEGA32 microcontrollerfrom Atmel. It controls the servo, gathers information fromthe sensors and places the information on the LCD screen.There is 32K of flash in the microcontroller and the softwareuses about 13K of that. Since the LCD uses a maximum of3.3V, the microcontroller is run at 3.3V.More

Interfacing the GP2D02 to a Microcontroller PIC andSweeping it with a Hobby Servo

The Sharp GP2D02 is a sensitive compact distance measuringsensor. It required two lines from a microcontroller in order to becontrolled. One line provides the signal to begin a measurementand also is used to provide a clock signal when transmitting thedistance measure, and the other line is used to transmit themeasurements back to the microcontroller. I interfaced the GP2D02to a 12CE519 microcontroller rather than my main CPU (16C77) inorder to free up processing time on the 16C77. The GP2D02 requiresan open collector on its input line, so I connected it through a diodeto the 12CE519. The GP2D02 output is connected directly to the12CE519. As I was limited to one GP2D02 IR sensor per robot,I used a hobby servo motor to sweep the GP2D02 through a 50degree pattern in the front of the robot. The servo used was aCirrus CS-70 Standard Pro Servo.

There are many different types of technologies and devicesused in measuring distance, some of them being: Radar, Sonar,Laser, Infrared and Ultrasonic. In this chapter Infrared andUltrasonic will be covered. Infrared uses light that is invisible tothe human eye. Also Infrared light bounces off almost everything.Its main disadvantage is that fluorescent lights generate it and thatcan cause interference. Ultrasonic uses sound that is inaudible tothe human ear. Its main advantage is that it is not sensitive to objectsof different colors and light reflecting properties. Its disadvantageis that some materials absorb sound and don’t reflect it.

PROJECT_6The components used in this project are one Sharp GP2D12Infrared distance sensors, one Ultrasonic circuit, a buzzer, a rotaryswitch circuit (refer to schematic from Project_5) also the parts fromProject_4. Fifteen of the twenty-two I/O pins of the PIC16F876 willbe used in this project.

Thursday, April 16, 2009

Abstract - This paper introduces a different approach tothe measurement of the time-of-flight of ultrasonic signals.Frequency variation monitoring and recording is used todetermine accurately the arrival time of the ultrasonic signal.A high speed Digital Signal Processor (D.S.P.) is used forboth: transmission and direct measurement of the frequencyof the incoming signal in every single period and with anaccuracy of about 0.1%. The proposed configuration offerssmall size and low cost solution to displacementmeasurements with a remarkable performance in terms ofaccuracy, range and measurement time.

THE SYSTEMThe configuration of the proposed system is based on thecapabilities of accurate time measurement of modern microcontrollers.The usual series of microcontrollers can not beused in this application mainly because of their relativelylow frequency of operation (clock frequency) which affectsthe accuracy of time measurement within one single period.They can not offer the required fast and accurate frequencymeasurement. A high performance system may therefore bebuilt only on a more powerful microcontroller. Largersystems (personal computer type, etc) are avoided forpractical reasons; the overall measurement system should becost-effective and small sized.

Ultrasonic Distance Sensor Implementedwith the Microcontroller ProjectLinear measurement is a problem that a lot ofapplications in the industrial and consumer marketsegment have to contend with. Ultrasonic technology isone of the solutions used by the industry. However, anoptimized balance between cost and features are a mustfor almost all target applications. The ultrasonic distancemeasurer (UDM) is used mainly when a non-contactmeasurer is required. This is the type of solution thisdocument explains using a simple robot toyimplementation.

DescriptionThe UDM is a demo that shows capability and performanceof the MC9RS08KA2 and the ultrasonic sensor to build adistance measurer. Figure 2 shows the basic building block ofthis project.

The firmware generates a 40 kHz burst signal. After the 10 cycleburst is completed, a variable that measures the distance isactivated. This variable measures the time sound takes to reboundand is used for distance calculation.

The burst signal goes to the ultrasonic transmitter (US Tx) and istransmitted as ultrasound through the air Figure 2. When the waveis reflected off an object, this wave is captured by the ultrasonicreceiver (US Rx.) This received signal is amplified because itattenuates as it travels. Afterwards, the signal goes back to themicrocontroller unit (MCU), filters it and calculates the distance.A 40 kHz interrupt is generated by the timer in the MCU. Toperform this, the keyboard interrupt (KBI) is enabled and detectsthe external signal. Every time the MCU is interrupted the counteris increased by three. And the variable used as a counter isdecreased by one for the entrances to the modulus timer module(MTIM) interrupt service routine (ISR). When this variable is biggerthan eight the ECHO signal is activated. The distance variable is thenset to 0. Refer to Figure 3 for timing diagram. For detailed informationabout the firmware see Figure 3.